An apparatus for detecting the color of an object may comprise an optical source and an optical receiver. The color of an object may be sensed by detecting at the optical receiver light emanating from the object. The color of the object may be, for example, determined by the interpreting the different outputs from respective red, green and blue color sub-receivers as different intensities. Calibration data is required for this interpretation.
Calibration may be achieved by using the optical source to illuminate an object of known color and processing the outputs from the respective red, green and blue color sub-receivers.